File photo. (ABC News)(WASHINGTON) -- During a press conference with Ukrainian Foreign Minister Pavlo Klimkin on Tuesday, U.S. Secretary of State John Kerry said that pro-Russian separatists have displayed an “appalling disregard for human decency” by allowing the remains of Malaysian Airlines crash victims to lay openly at the scene for days and barring international observers from accessing the site.

Both Kerry and Klimkin said there is still debris and human remains at the crash site that need to be investigated.

“They still can’t even ensure that all of the victims’ remains have been removed, and that is an unsupportable burden for any family to have to bear, and it is an unacceptable standard for behavior, period,” Klimkin said.

Kerry added that the United States and the European Union are working on additional sanctions on Russia. When asked when they would be imposed, he responded “forthwith.”